U.S. patent application number 10/506219 was filed with the patent office on 2005-06-09 for dynamic intervertebral implant.
This patent application is currently assigned to Fixano. Invention is credited to Martin, Jean-Jacques, Matge, Guy.
Application Number | 20050125063 10/506219 |
Document ID | / |
Family ID | 27772167 |
Filed Date | 2005-06-09 |
United States Patent
Application |
20050125063 |
Kind Code |
A1 |
Matge, Guy ; et al. |
June 9, 2005 |
Dynamic intervertebral implant
Abstract
The implant includes two side walls resting against the
vertebral end-plates and an intermediate wall joining the
supporting walls. The implant can be deformed for insertion between
the vertebrae to be treated to restore the attenuated mobility of
the vertebrae, and includes mounting elements mounting on the
vertebrae. The side walls have a curved shape, whose convexity is
oriented towards the outside of the implant; the intermediate wall
has a curved shape, whose convexity is oriented towards the outside
of the implant such that it does not form any pronounced angles
with the supporting side walls. The supporting side walls and the
intermediate wall, have a partially oval shape; and the mounting
elements are configured such that the implant can be mounted on the
vertebrae.
Inventors: |
Matge, Guy; (Mamer, LU)
; Martin, Jean-Jacques; (Bourg En Bresse, FR) |
Correspondence
Address: |
YOUNG & THOMPSON
745 SOUTH 23RD STREET
2ND FLOOR
ARLINGTON
VA
22202
US
|
Assignee: |
Fixano
|
Family ID: |
27772167 |
Appl. No.: |
10/506219 |
Filed: |
September 1, 2004 |
PCT Filed: |
March 13, 2003 |
PCT NO: |
PCT/FR03/00799 |
Current U.S.
Class: |
623/17.13 |
Current CPC
Class: |
A61F 2002/30571
20130101; A61B 17/7059 20130101; A61F 2/30767 20130101; A61F
2230/0093 20130101; A61F 2002/30578 20130101; A61F 2002/30616
20130101; A61F 2250/0029 20130101; A61F 2002/2835 20130101; A61F
2002/30014 20130101; A61F 2/30771 20130101; A61F 2/442 20130101;
A61F 2002/30784 20130101; A61F 2/4455 20130101; A61F 2002/30892
20130101; A61F 2310/00023 20130101; A61F 2002/30879 20130101; A61B
17/86 20130101 |
Class at
Publication: |
623/017.13 |
International
Class: |
A61F 002/44 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 15, 2002 |
FR |
0203252 |
Claims
1. Intervertebral implant (1), notably intended for the treatment
of cervical vertebrae (10) by anterior approach route, comprising
two lateral walls (2) bearing against the vertebral plates and an
intermediate wall (3) for connection of these lateral bearing
walls, this implant (1) being deformable elastically for the
insertion thereof between the vertebrae (10) to be treated and to
enable restoration of dampened mobility of these vertebrae (10),
and including means (4) for the assembly thereof to these vertebrae
(10); Implant (1) characterized in that: said lateral bearing walls
(2) show, seen laterally, curved shapes with their convexity turned
to the outside of the implant (1); said intermediate wall (3) shows
a curved shape, with its convexity turned to the outside of the
implant (1), and is such that it does not form any marked angles
with said lateral bearing walls (2), these lateral bearing walls
(2) and this intermediate wall (3) having thus, seen laterally,
partial oval "water drop"-like shape; and the means (4) for
fastening the implant (1) to the vertebrae (10) are designed to
enable non rigid assembly of this implant (1) to these vertebrae
(10), i.e. authorising slight deformation of the implant (1) with
respect to the vertebrae (10) as the latter are moving.
2. Implant (1) according to claim 1, characterized in that said
intermediate wall (3) is so shaped as, when not deformed, to
maintain said lateral bearing walls (2) at a distance from one
another which is slightly greater than the height of the
intervertebral space to be restored.
3. Implant (1) according to claim 1, characterized in that the
implant (1) is made simply by folding a single piece of appropriate
material, notably a sheet metal flank.
4. Implant (1) according to claim 3, characterized in that the
material used is the titanium, aluminium and vanadium alloy known
as "TA6V".
5. Implant (1) according to claim 1, characterized in that said
attachment means of the implant (1) to the vertebrae (10) comprise
at least one series of ribs (4) parallel to one another, with sharp
free ridges, protruding from the external face of the free end of a
lateral bearing wall (2).
6. Implant (1) according to claim 5, characterized in that it
comprises two series of ribs (4), the one on one of the lateral
bearing walls (2), the other on the other lateral bearing wall (2),
and in that it exhibits a "lower" lateral bearing wall (2), i.e.
bearing against the lower vertebra during placement, with a length
greater than that of the other lateral bearing wall (2).
7. Set of intervertebral implants comprising at least one
intervertebral implant (1) according to claim 1, characterized in
that it comprises at least one other intervertebral implant (11),
intended to realise a fusion between the two vertebrae (10) to be
treated; this other implant (11), so-called "fusion" implant, has a
structure similar to that of the implant (1) described above, but
comprises attachment means which enable the rigid assembly thereof
to the vertebrae (10) treated.
8. Set of implants according to claim 7, characterized in that said
means enabling to attach the "fusion" implant (11) comprise at
least one tab (5) integral with one of said lateral bearing walls
(2), drilled with a reception hole of an anchoring screw (6), this
screw (6) being intended for insertion in the body of the
corresponding vertebra (10).
9. Set of implants according to claim 7, characterized in that said
lateral bearing walls (2) of the "fusion" implant (11) exhibit
surface coverings promoting their osteo-integration and/or comprise
holes which communicate the space delineated between them, with the
exterior of the implant (1).
10. Set of implants (1) according to claim 9, characterized in that
the "fusion" implant (11) receives a bony graft placed in the space
delineated between said lateral bearing walls (2).
11. Implant (1) according to claim 2, characterized in that the
implant (1) is made simply by folding a single piece of appropriate
material, notably a sheet metal flank.
12. Set of implants according to claim 8, characterized in that
said lateral bearing walls (2) of the "fusion" implant (11) exhibit
surface coverings promoting their osteo-integration and/or comprise
holes which communicate the space delineated between them, with the
exterior of the implant (1).
Description
[0001] The present invention relates to an intervertebral implant,
notably intended for the treatment of cervical vertebrae by
anterior approach route.
[0002] It is known to use intervertebral implants to restore the
anatomic intervertebral space between two vertebrae. However, the
existing implants are not completely satisfactory, in particular as
regards the treatment of cervical vertebrae by anterior approach
route, either because they do not restore perfectly the
intervertebral space, or because they form obstacles to the
movements of the vertebrae, or because they induce risks of
insertion in the vertebral plates, or because they are difficult to
implant, or because their durability or the anchoring thereof is
questionable.
[0003] The document U.S. Pat. No. 5,749,16 describes a fusion cage
slit laterally to enable the application of stresses on a graft
contained in the wedge and/or for restoring anatomic mobility
between two vertebrae.
[0004] This implant is not intended for treating cervical vertebrae
by anterior approach route, and the implant according to the
invention does not comprise any lateral slot.
[0005] There is also provided, by the document WO 01/62190, an
intervertebral implant comprising a U-shaped body seen laterally,
i.e. showing two lateral branches resting against the vertebral
plates and a posterior "wall". This body is deformable elastically
for the insertion thereof between the vertebrae to be treated and
to enable restoration of the mobility of the vertebrae, and forms
protruding tabs for the attachment thereof to the vertebrae.
[0006] This implant is estimated as not satisfactory from the point
of view of the restoration of an intervertebral space with mobility
of the vertebrae. Indeed, the screw attachment of this implant is
considered as not suitable for such a restoration, taking into
account the risks induced of a vertebral fusion by growth of the
bony cells, which may result in immobilisation of the vertebrae.
Moreover, the resistance of this implant to the repeated stresses
transmitted by these vertebrae is considered as questionable.
[0007] The purpose of the present invention is to remedy these
shortcomings.
[0008] Its main object consists thus in providing an intervertebral
implant capable of restoring adequate anatomic space between two
vertebrae while keeping, in all certainty over time, the relative
mobility of the two vertebrae treated.
[0009] Another object of the invention is to provide an
intervertebral implant offering perfect resistance to the repeated
stresses transmitted by these vertebrae.
[0010] The implant in question comprises, as known, two lateral
walls bearing against the vertebral plates and an intermediate wall
for connection of these lateral bearing walls, this implant being
deformable elastically for the insertion thereof between the
vertebrae to be treated and to enable restoration of dampened
mobility of these vertebrae, and including means for the assembly
thereof to these vertebrae.
[0011] According to the invention,
[0012] said lateral bearing walls show, seen laterally, curved
shapes with their convexity turned to the outside of the
implant;
[0013] said intermediate wall shows a curved shape, with its
convexity turned to the outside of the implant, and is such that it
does not form any marked angles with said lateral bearing walls,
these lateral bearing walls and this intermediate wall having thus,
seen laterally, partial oval "water drop"-like shape; and
[0014] the means for fastening the implant to the vertebrae are
designed to enable non rigid assembly of this implant to these
vertebrae, i.e. authorising slight deformation of the implant with
respect to the vertebrae as the latter are moving.
[0015] The curved shaped of said lateral walls enables these walls
to adapt accurately to the shape of the respective faces of the
vertebral plates, thereby ensuring certain retention of the implant
between the vertebrae.
[0016] Once in place, the implant does not oppose the movements of
the vertebrae because of the deformability of the intermediate wall
thereof; the risk of inserting the implant in the vertebral plates
is consequently vastly reduced, if not eliminated, the more so
because said lateral walls possess wide contact surfaces with the
vertebral plates.
[0017] The absence of marked angles between said lateral bearing
walls and said intermediate wall enables to avoid, on the body of
the implant, any concentration of the loads transmitted by the
vertebrae at a given location of this body, and enables
consequently to this implant to have perfect resistance to these
loads over time.
[0018] The shape aforementioned of the body of the implant enables
besides certain deformation of the implant with respect to the
vertebrae when the latter are moving, this deformation being not
prevented by said means for fastening this implant to the vertebrae
and being only limited by the latter.
[0019] This mobility prevents any risks of fusion of the
intervertebral space further to bony cells growing around the
implant, and therefore to keep total mobility of the vertebrae
relative to one another over time.
[0020] Preferably, said intermediate wall is so shaped as, when not
deformed, to maintain said lateral bearing walls at a distance from
one another which is slightly greater than the height of the
intervertebral space to be restored.
[0021] This intermediate wall is therefore slightly constrained
when the implant is placed and enables to ensure, by elastic
return, slight support of the upper vertebra relative to the lower
vertebra.
[0022] Advantageously, the implant is made simply by folding a
single piece of appropriate material, notably a sheet metal flank.
The material used may be, notably, titanium, aluminium and vanadium
alloy, known as "TA6V".
[0023] According to a preferred embodiment of the invention, said
attachment means of the implant to the vertebrae comprise at least
one series of ribs parallel to one another, with sharp free ridges,
protruding from the external face of the free end of a lateral
bearing wall.
[0024] These ribs are intended for insertion in the anterior zone
of the body of the adjacent vertebra.
[0025] The implant may comprise two series of ribs, the one on one
of the lateral bearing walls, the other on the other lateral
bearing wall. For treating cervical vertebrae, the implant exhibits
advantageously a "lower" lateral bearing wall, i.e. bearing against
the lower vertebra during placement, with a length greater than
that of the other lateral bearing wall.
[0026] The implant described above may be part of a set of implants
including at least one other intervertebral implant, intended to
realise a fusion between the two vertebrae to be treated; this
other implant, so-called "fusion" implant, has a structure similar
to that of the implant described above, but comprises attachment
means which enable the rigid assembly thereof to the vertebrae
treated.
[0027] Preferably, in such a case, said means enabling to attach
the "fusion" implant comprise at least one tab integral with one of
said lateral bearing walls, drilled with a reception hole of an
anchoring screw, this screw being intended for insertion in the
body of the corresponding vertebra.
[0028] Said lateral bearing walls of the "fusion" implant may
exhibit surface coverings promoting their osteo-integration and/or
comprise holes which communicate the space delineated between them,
with the exterior of the implant. A bony graft may then be placed
in this space.
[0029] For better understanding thereof, the invention is again
described below with reference to the appended schematic drawing,
representing for non limiting exemplification purposes, a possible
embodiment possible of the intervertebral implant in question, and
a "fusion" implant included in a set of implants also affected,
said set comprising said intervertebral implant according to the
invention and said "fusion" implant.
[0030] FIG. 1 is a perspective view of the intervertebral implant
in question;
[0031] FIG. 2 is a side view thereof after placement thereof;
[0032] FIG. 3 is a perspective view of said "fusion" implant, and
FIG. 4 is a side view of this "fusion" implant after placement.
[0033] FIGS. 1 and 2 represent an intervertebral implant 1 for the
treatment of cervical vertebrae 10 by anterior approach route.
[0034] As it appears, the implant 1 is realised by folding a given
piece of material and exhibits, seen laterally, i.e. in the
sagittal plane after implantation, a curved shape delineating two
lateral bearing walls 2 and one intermediate wall 3.
[0035] Said piece of material is a sheet flank made of titanium,
aluminium and of vanadium alloy known as "TA6V".
[0036] The lateral walls 2 show, seen laterally, domed shapes on
the greatest portion of their length, the convexities thereof being
turned towards the exterior of the implant 1. At their free end
zones, these lateral bearing walls 2 are rectilinear in shape and
comprise each a series of ribs 4.
[0037] The length of the "lower" wall 2, i.e. abutting the lower
vertebra during implantation, is greater than that of the other
wall 2.
[0038] The intermediate wall 3 has a curved shape whereof the
convexity is turned towards the exterior of the implant. As appears
clearly, it does not form any marked angles with the lateral
bearing walls 2, these lateral bearing walls 2 and this
intermediate wall 3 having thus, seen laterally, partially oval
"water drop`-like shape.
[0039] The intermediate wall 3 is moreover deformable elastically
between a neutral form, wherein it maintains normally the walls 2
at a distance from one another which is slightly greater than the
height of the intervertebral space to be restored, and a
constrained shape, wherein said wall 3 enables to bring the free
ends of both walls 2 together. This bringing together is such that
it enables to reduce the height of the implant 1 so that such
height is smaller than the height of the intervertebral space to be
restored.
[0040] The ribs 4 are parallel to one another and protrude from the
free end zone of each wall 2, towards the exterior of the implant
1. Each of them is delineated by an anterior face perpendicular to
the longitudinal direction of the implant 1 and by a tilted
posterior face, forming an angle of approximately 500 with the
anterior face. These ribs 4 thus exhibit relatively sharp free
ridges.
[0041] The implant 1 represented for exemplification purposes
exhibits the following dimensions:
[0042] maximum dimension of the implant in the sagittal plane:
approximately 17 mm;
[0043] difference in length of the walls 2: approximately 1 mm;
[0044] dimension of the implant in the front plane: approximately
18 mm;
[0045] thickness of said flank at the walls 2 and of the wall 3:
approximately 1 mm;
[0046] maximum thickness of the implant 1, at the exterior domed
faces of the lateral walls 2: approximately 7 mm;
[0047] curvature radius of the upper half of the intermediate wall
3: approximately 2.7 mm;
[0048] curvature radius of the lower half of the intermediate wall
3: approximately 3.3 mm;
[0049] curvature radius of the domed zone of the upper lateral wall
2: 10 mm;
[0050] curvature radius of the domed zone of the lower lateral wall
2: approximately 25 mm.
[0051] In practice, the walls 2 are brought towards one another by
deformation of the wall 3, to enable insertion of the implant 1
between the vertebral plates of the two vertebrae 10 to be treated,
then, once said insertion is completed, the walls 2 are released,
which presses said walls against these vertebral plates. The ribs 4
are inserted in the vertebral plates and enable non rigid assembly
of the implant 1 to these vertebrae or tissues, i.e. allowing
slight deformation of the implant with respect to the vertebrae as
the vertebrae are moving, while opposing any expulsion of the
implant.
[0052] The domed shape of the walls 2 enables these walls to match
precisely the shape exhibited by the respective faces of these
vertebral plates, and ensures certain retention of the implant
between the vertebrae 10. The elastic stress remaining in the wall
3 enables to maintain the ribs 4 inserted in the vertebrae 10.
[0053] The "fusion" implant 11 shown on FIGS. 3 and 4 have a
structure similar to that of the implant 1 described above, except
that the walls 2 comprise two tabs 5, interconnected therewith and
extend their free ends.
[0054] Each of these tabs 5 is attached to the end of the wall 2
which supports the latter by two curved lateral connection zones,
which enable to ensure perfectly solid link of this tab 5 and of
the wall 2, and is drilled with a hole accommodating an anchoring
screw 6. This screw 6 is intended to be inserted in the body of the
corresponding vertebra 10, as shown on FIG. 4.
[0055] Each tab 5 forms an angle of the order of 120.degree. with
the general antero-posterior direction of the wall 2 to which said
tab is attached, and exhibits a thickness greater than that of the
remainder of the implant 1. This thickness is approximately 1.5 mm
in the example represented.
[0056] The "fusion" implant 11 is used to realise a fusion between
the two vertebrae 10 to be treated.
[0057] It appears from the foregoing that the invention brings a
decisive improvement to the anterior technique, by providing an
intervertebral implant enabling perfect restoration of the
intervertebral space, without opposing the movements of the
vertebrae, without inducing any risks of insertion in the vertebral
plates nor of risk of fusion by growing bony cells, while being
easy to be implanted and whereof the durability is not
questionable.
[0058] It goes without saying that the invention is not limited to
the embodiment described above for exemplification purposes, but it
includes conversely all the embodiment variations covered by the
appended claims.
* * * * *